1. Field of the Invention
The present invention generally relates to an apparatus used in the conveying of particulate materials. More particularly, the invention relates to hopper bins and charging adapters used in the conveying of particulate materials.
2. Description of the Prior Art
In the process of conveying particulate materials, it is often beneficial to utilize a hopper assembly. The hopper assembly may be used in conjunction with other machinery, for example, bulk bag dischargers, mixing bins, or conveyors. The hopper assemblies often comprise a hopper bin and a charging adapter. Such hopper bins are generally cone-shaped, extending upwardly from a discharge opening outwardly towards a larger receiving opening. The charging adapters generally act as the transition between the output of material and a conveying means.
Generally, particulate materials do not flow freely when the angle at which the material is flowing is less than the material's angle of repose. As a result of the general configuration of prior hopper bins and charging adapters, a stable arch, bridge, or "rat hole" develops within the material and flow ceases. Even if flow does not completely cease, other problems such as erratic flow, flushing, segregation, and degradation of the material occur. These problems are enhanced when the surfaces between which the material is flowing are diametrically opposed.
In attempts to overcome these difficulties, prior art hoppers have been designed with larger discharge openings and steep hopper walls which are intended to be steeper then the angle of repose. However, increasing the size of the discharge opening provides less control over the material flow. Also, when the opening is larger than the conveyor which is being used, the conveyor does not move all of the material which exits the opening, and the non-moving material generally acts as a platform which prevents the flow of material above it. With respect to increasing the hopper wall angle, the angle of repose for some materials approaches ninety degrees and therefore a hopper which can be utilized with any such material would need substantially vertical walls. This causes the hoppers to take up more space and have a higher receiving opening plane, thereby making it more difficult to directly load the hopper bin.
In the present invention, the hopper assembly includes a hopper bin having a substantially trapezoidal discharge opening and a charging adapter which has sheer planes that cause the bulk material to "break" and flow before arching or bridging occurs.